Mesh networks are composed of two or more electronic devices each containing at least one transceiver. The electronic devices use their transceivers to communicate with one another and/or a central device. If the device wishes to communicate with another device that is out of transmission range, the device may communicate via multi-hop communication through other devices. Because the devices may rely on a small source of stored energy (e.g., batteries or a capacitor), it is desirable for those devices to reduce power. In particular, the transceiver, when placed in receive mode, can require significant power and quickly drain a small source of stored energy.
In the advanced metering infrastructure (AMI) market, for example, there are a class of devices (e.g., water and gas meters) that must operate for many years on modest energy capacity (e.g., batteries). Given the power draw of existing transceivers and limited capacity of cost-effective energy storage, such devices must operate their transceivers with a very low average duty cycle.
A challenge with channel hopping at very low duty cycles is managing the time synchronization error. In particular, uncertainties in time synchronization normally occur due to clock drift, and such uncertainties are problematic in channel-hopping networks since nodes must be configured to the same channel at the same time. Maintaining tight time synchronization requires nodes to communicate timing information relatively frequently, compromising the lifetime or cost of the device's energy storage.